Pulse oximetry offers a non-
invasive way of measuring
oxygenation levels compared to
arterial blood gas sampling, which
is invasive, can be a painful, is more
time-consuming, and is usually
performed by specialist respiratory
nurses. Pulse oximetry is now a
very affordable and easy first-line
clinical investigation that can be used
to assess baseline resting oxygen
saturation and to detect the presence
of hypoxaemia (abnormally low level
of oxygen in the blood